Problem: Multiply. $2.8 \times 0.72 = $
Answer: $28 \times 72$ and $2.8 \times 0.72$ multiply the same digits in the same order. So, the product of both problems will also have the same digits in the same order. Let's multiply $28 \times 72$. Then we can estimate to place the decimal point in the product of $2.8 \times 0.72$. $\begin{aligned} 28&\\ \underline{ \times 72}&\\ 16}\\ 40}\\ 560}\\ \underline{+1{,}400}}\\ 2{,}016 \end{aligned}$ Let's estimate to place the decimal in $2.8 \times 0.72$. $\begin{aligned} 2.8 \times 0.72 &\approx 3 \times 0.7\\\\ &\approx \dfrac{3}{1}\times \dfrac{7}{10}\\\\ &\approx \dfrac{21}{10}\\\\ &\approx 2.1 \end{aligned}$ Where can we place the decimal in $2016$ to get a product close to $2.1$ ? $2.8 \times 0.72 = 2.016$